Influence of Fe-doping on the structural, optical and luminescent behavior of ZnO thin films deposited by spin coating technique

The current work describes the fabrication of Fe-doped zinc oxide thin films on a glass substrate using sol-gel spin coating technique. The undoped and Fe-doped ZnO films were annealed at the 400 °C for 3 h. The structural, optical, morphological and luminescent features were explored by using X-ray diffraction (XRD), diffuse reflectance, scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy techniques. It was noted that XRD patterns showed the polycrystalline nature and demonstrated a hexagonal wurtzite structure of Zn1-xFexO. With the rise in Fe ratio, the grain sizes of the deposited films start to cut as revealed from the SEM images. Interestingly, no variation has been noted in the transmittance value in the visible region. However, a lessening in the band-gap energy with an increment in the Fe concentration has been seen. PL curves exhibit ultraviolet emission peaks at 398 and 485 nm that are associated with the near band edge emission (NBE) and defect emission peak. It has been noted that the NBE emission shifts to longer energy with the rise in the Fe ratio. These results demonstrated the applicability of ZnO thin films as a suitable material for light emitting applications.